1 2 inch thick angle iron.
Fixing sagging roof over garage.
The first step is to the basement first.
Any sagging will gradually be lifted and by the time you have finished the garage roof repair your roof should but upright again.
Use instructions from my page how to fix a sagging floor before you continue trying to fix the roof sagging issue.
Step 4 strengthen the beams.
With a pair of rafters pushed apart to straighten the sagged roof a new mid span cross tie will be nailed in place.
Sagging rafters can lead to serious problems with the entire roofing system.
If necessary use something to force the roof up while you work the beams into place and fasten them.
If the line does not continually follow the bottom of the beam and the bottom of the beam is below the line the beam is sagging.
Check the ceiling for sagging by attaching a string on one end of the beam and run it along the bottom edge of the beam.